Primary interferon resistance and treatment response in chronic hepatitis C infection: a pilot study

Only 30% of patients with chronic hepatitis C virus genotype 1 (HCV-1) infe ction achieve a sustained virological response to interferon and ribavirin combination therapy. We prospectively assessed decline in viral load 24 h a fter one dose of interferon alfa as a predictor of non-response to 6 months of treatment with interferon and ribavirin. Interferon sensitivity was mea sured before initiation of combination therapy. We measured viral load in 2 9 consecutive patients, who had not previously been treated with interferon and who were chronically infected with HCV-1 within 24 h after one dose of 5 MU or 10 MU interferon alfa-2b, and 14 days of daily 5 MU interferon alf a-2b. A 24 h viral load decline by less than 70% of baseline after 5 MU int erferon was the best pretreatment measure to identify non-responders (speci ficity 100%, n=10, 95% CI 74-100], sensitivity 83% [15/18], 59-96]).